Posted
by
Soulskillon Saturday September 18, 2010 @08:20PM
from the everything-old-is-new-again dept.

oztiks writes with this excerpt from The H:
"A vulnerability in the 32-bit compatibility mode of the current Linux kernel (and previous versions) for 64-bit systems can be exploited to escalate privileges. For instance, attackers can break into a system and exploit a hole in the web server to get complete root (also known as superuser) rights or permissions for a victim's system. According to a report, the problem occurs because the 32-bit call emulation layer does not check whether the call is truly in the Syscall table. Ben Hawkes, who discovered the problem, says the vulnerability can be exploited to execute arbitrary code with kernel rights. ... Hawkes says the vulnerability was discovered and remedied back in 2007, but at some point in 2008 kernel developers apparently removed the patch, reintroducing the vulnerability. The older exploit apparently only needed slight modifications to work with the new hole."

You're talking about git submodules and I'm gonna go ahead and guess that the answer you'll receive from the kernel folks about that is a big fat "no". Maybe if Git had usable project hierarchies, things might be different.

Also to note: even Git can't fix stupid policy or stupid programming decisions.

there is a workaround of disabling 32bit binaries (I'd paste a link if Google Chrome dev channel would let me... for some reason I can only paste into/.'s comment box before I've typed anything else, I'll follow-up with it), but of course you may need them depending on what your machine does.

I'm running a kernel base don 2.6.35.4 but with all 3 of those commits applied (note the last one tries to modify an arch/tile/ file which doesn't exist in 2.6.35.4, just ignore that) and can confirm that neither exploit works.

A LOT of hosts still get rooted because of weak passwords. A LOT of valuable hosts get rooted through social engineering. Just because you've seen rooted hosts, doesn't mean that there is any wide-scale deployment of anything.

I've got some very expensive commercial software on my nodes which is produced by utter idiots that have put 32bit binaries in directories called "linux64". They've been migrating their stuff from 32bit to 64bit since 2003 so they'll get there eventually. Until then it's a mixed system with a lot of undocumented messing about to install their software.Everything else on there was compiled for 64 bit.

News like this makes me smile that I decided to use Gentoo Hardened 64-bit nomultilib whenever I built servers. Makes it harder if the software needed to run is only available as 32-bit binaries, but I haven't run into any yet that I've needed.

Since it has no 32-bit emulation layer, this is probably one of the few 64-bit linux not affected (without a patch).

The vulnerability is affecting kernels compiled with 32-bit compatibility support. Enabling this option seems to be the default, even on x64 systems that do not have 32-bit libraries and cannot execute 32-bit binaries. You can say

zcat/proc/config.gz | grep CONFIG_IA32_EMULATION

to see if you have it on. More info [linuxquestions.org], and the origina [sota.gen.nz] hack [sota.gen.nz].

BTW, is it the norm for kernel developers to sign-off commits for their own patches? Maybe if someone else was responsible for reviewing and signing-off on the patch, this could have been caught ahead of time? Another person could have missed it too, but then again, maybe not.

"But we must warn you: there is a special user on every UNIX system, called the super-user, who can read or modify any file on the system. The special loginm name root carries super-user privledges...."

The offending patch was authored and committed by a Redhat developer. Since this guy made his own company's product insecure for their clients, I'd say that Redhat could very well fire him. Whether they will or not depends on the company. Besides, do you know of a Microsoft (or any closed source software company) employee being fired based on their coding vulnerable software? How about a CEO being fired for selling vulnerable software to the public? Where's the accountability there?

RHEL was never affected. Red Hat BugID 630551 [redhat.com] states:"This issue did not affect the version of Linux kernel as shipped with Red HatEnterprise Linux 3, 4, and 5 as it did not include upstream commit 7034632dthat introduced the problem. It did not affect Red Hat Enterprise MRG as the/dev/sequencer device file is restricted to root access only."

Further, Red Hat states for CVE-2010-3080 [redhat.com] that the commit upstream that brought the bug back was never allowed into Red Hat kernels:"This issue did not affect the version of Linux kernel as shipped with Red Hat Enterprise Linux 3, 4, and 5 as it did not include upstream commit 7034632d that introduced the problem."

I guess you get what you pay for.

I'll be curious to see in the next few days if downstream from Red Hat followed Red Hat's same kernel compile options. Some prominent downstream versions would be CentOS and Oracle's OEL.

Yeah but none of those exploits is in the Windows 7 kernel itself (which is rarely ever patched). They'll all be related to other components distributed with the operating system. This could be many things including Windows Media Player and IIS. If you want to compare the number of Linux patches with Windows Updates you would need to compare the Windows patches to the patches of s Linux distro not just the Linux kernel itself.

Anyway, no matter how painful it might be for the person who reverted the patch, the issue does need to be investigated in order to find out how to detect other instances and how to stop it from happening again.

It seems to me that the critical line of code reloading EAX was deleted because the committer couldn't see why it was necessary, and there was no comment in the code to explain its purpose. With no comment, and no unit test to guard against regressions (and I recognise that isn't always practical), this was an accident waiting to happen.

Unfortunately the Burroughs refused to run mainframe software with such bugs. Burroughs died.IBMs ran such software without complaint. IBM survived.Since the programs certainly had some design errors, it really becomes a question of which erroneous behaviors are silliest. Often the "most correct" are the silliest.

DESCRIPTION
sudo allows a permitted user to execute a command as the superuser or another user

Outside geek circles "root" doesn't mean anything, but superuser is at least somewhat meaningful. Though most don't actually deal with it at all anymore, they're in a sudo group so they only ever user their account and some applications ask them to reenter their password to become administrators. To most people "root" is more like "system" than "superuser" to most people these days.